1. Field of the Invention
The present invention relates to an electronic keyboard instrument, such as an electronic piano.
2. Description of the Related Art
As described in Japanese Patent Application Laid-Open (Kokai) Publication No. H05-73029, an electronic keyboard instrument is conventionally known that is configured to achieve a key-press feel similar to that of an acoustic piano. In this electronic keyboard instrument, a heavy hammer member, which is provided under a key in a manner to be rotatable in a vertical direction, rotates against its own weight in response to a key depression operation, thereby applying a predetermined action load to the key.
This type of electronic keyboard instrument is structured such that a hammer switch that is turned ON by a hammer member is provided on the lower surface of a switch board, and a key switch that is turned ON and OFF by a key is provided on the upper surface of the switch board. As a result of this structure, in consecutive key-striking such as a trill in which the same key is repeatedly struck, a musical sound can be generated even when the same key is depressed before the key and the hammer member return from a final position to an initial position after rotating.
In an electronic keyboard instrument such as this, after a key is depressed and the key switch is turned ON thereby, the hammer member rotates to be displaced towards the final position, whereby the hammer switch is turned ON, and an instruction to start generating a musical sound is given. In an ordinary performance, when the hammer member and the key rotate to return from the final position to the initial position, the key switch is turned OFF after the hammer switch is turned OFF, and as a result of the key switch being turned OFF, the generation of the musical sound is stopped and the musical sound is silenced.
Conversely, in consecutive key-striking in which the same key is repeatedly struck, the key switch is not turned OFF when the hammer member rotates to return from the final position to the initial position after a key is depressed and the generation of a musical sound starts, and remains turned ON after the hammer switch is turned OFF. Then, when the same key is depressed, the hammer switch is turned ON again without the generation of the musical sound being stopped. Accordingly, in this electronic keyboard instrument, musical sound can be consecutively generated, even when consecutive key-striking in which the same key is repeatedly struck, such as a trill, is performed.
However, since a conventional electronic keyboard instrument such as this is configured such that a hammer switch that is turned ON by a hammer member is provided on the lower surface of a switch board, and a key switch that is turned ON and OFF by a key is provided on the upper surface of the switch board, a problem so-called chattering arises therein. In chattering, after a key is depressed and the key switch is turned ON thereby, when the hammer member rotates to be displaced towards the final position and the hammer switch is turned ON, the impact of the hammer member on the hammer switch is transmitted to the key switch of the switch board, causing the key switch to turn OFF for an instant.